Method of producing exchange coupling film and method of producing magnetoresistive sensor by using exchange coupling film

A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetwen on a side opposite said ferromagnetic layer, said method comprising:

• forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer;
• depositing on said seed layer an antiferromagnetic layer comprising an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof,
• elevating a sputtering gas pressure during said depositing so that a composition ratio of said element X in said antiferromagnetic layer progressively decreases as distance from said seed layer increases;
• decreasing said sputtering gas pressure during said depositing so that said composition ratio of said element X in said antiferromagnetic layer progressively increases as distance from said seed layer further increases;
• and
• effecting a heat-treatment after said forming and said depositing, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.

A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said method comprising:

• forming said seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer;
• depositing on said seed layer, an antiferromagnetic layer comprising an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof;
• elevating a sputtering gas pressure during said depositing so that a composition ratio of said elements X+X′ in said antiferromagnetic layer progressively decreases as distance from said seed layer increases;
• decreasing said sputtering gas pressure during said depositing so that said composition ratio of said elements X +X′ in said antiferromagnetic layer progressively increases as distance from said seed layer further increases;
• and
• effecting a heat-treatment after said forming and said depositing, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.

A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which said layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said antiferromagnetic layer comprising a first antiferromagnetic layer, a second antiferromagnetic layer and a third antiferromagnetic layer said method comprising:

• forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer;
• forming said antiferromagnetic layer such that said third antiferromagnetic layer is adjacent to said seed layer, said first antiferromagnetic layer is adjacent to said ferromagnetic layer, and said second antiferromagnetic layer is between said first and said third antiferromagnetic layers, wherein each of said first, said second, and said third antiferromagnetic layers comprise an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, such that said second antiferromagnetic layer has a smaller composition ratio of said element X than said first and said second antiferromagnetic layers;
• and
• effecting a heat-treatment after said forming of said seed layer and said forming of said antiferromagnetic layer, such that an exchange coupling magnetic field is developed at said interface between said antiferromagnetic layer and said ferromagnetic layer.

A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said antiferromagnetic layer comprising a first antiferromagnetic layer, a second antiferromagnetic layer, and a third antiferromagnetic layer said method comprising:

• forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer;
• forming said antiferromagnetic layer such that said third antiferromagnetic layer is adjacent to said seed layer, said first antiferromagnetic layer is adjacent to said ferromagnetic layer, and said second antiferromagnetic layer is between said first and said third antiferromagnetic layer, wherein each of said first, said second, and said third antiferromagnetic layers comprise an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof, such that said second antiferromagnetic layer has a smaller composition ratio of said element X than said first and said second antiferromagnetic layers;
• and
• effecting a heat-treatment after said forming of said seed layer and said forming of said antiferromagnetic layer, such that an exchange coupling magnetic field is developed at said interface between said antiferromagnetic layer and said ferromagnetic layer.